Water

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15 pages, 3289 KiB

Open AccessArticle

Regional Downscaling of Copernicus ERA5 Wave Data for Coastal Engineering Activities and Operational Coastal Services

by Giorgio Bellotti, Leopoldo Franco and Claudia Cecioni

Water 2021, 13(6), 859; https://doi.org/10.3390/w13060859 - 22 Mar 2021

Cited by 8 | Viewed by 2856

Hindcasted wind and wave data, available on a coarse resolution global grid (Copernicus ERA5 dataset), are downscaled by means of the numerical model SWAN (simulating waves in the nearshore) to produce time series of wave conditions at a high resolution along the Italian [...] Read more.

Hindcasted wind and wave data, available on a coarse resolution global grid (Copernicus ERA5 dataset), are downscaled by means of the numerical model SWAN (simulating waves in the nearshore) to produce time series of wave conditions at a high resolution along the Italian coasts in the central Tyrrhenian Sea. In order to achieve the proper spatial resolution along the coast, the finite element version of the model is used. Wave data time series at the ERA5 grid are used to specify boundary conditions for the wave model at the offshore sides of the computational domain. The wind field is fed to the model to account for local wave generation. The modeled sea states are compared against the multiple wave records available in the area, in order to calibrate and validate the model. The model results are in quite good agreement with direct measurements, both in terms of wave climate and wave extremes. The results show that using the present modeling chain, it is possible to build a reliable nearshore wave parameters database with high space resolution. Such a database, once prepared for coastal areas, possibly at the national level, can be of high value for many engineering activities related to coastal area management, and can be useful to provide fundamental information for the development of operational coastal services. Full article

(This article belongs to the Special Issue Coastal Sediment Management: From Theory to Practice)

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28 pages, 4389 KiB

Open AccessArticle

User Needs Analysis for the Definition of Operational Coastal Services

by Serena Geraldini, Antonello Bruschi, Giorgio Bellotti and Andrea Taramelli

Water 2021, 13(1), 92; https://doi.org/10.3390/w13010092 - 4 Jan 2021

Cited by 10 | Viewed by 3546

Abstract

According to the global growth of the “Blue economy”, coastal zones are under pressure from both land and marine side economic activities. The fragmentation of sectorial interests and legislation along the coasts has led to the need for bridging knowledge (data/information and methods/tools) [...] Read more.

According to the global growth of the “Blue economy”, coastal zones are under pressure from both land and marine side economic activities. The fragmentation of sectorial interests and legislation along the coasts has led to the need for bridging knowledge (data/information and methods/tools) and governance (decision-makers at every level) in order to ensure sustainable economic development and social and ecosystem resilience. This poses the need for an interaction process that associates user needs to the European and national legislative framework to create a policy-oriented demand of Copernicus Earth Observation services in coastal areas. Such goals need a strong and effective system to monitor compliance and to assess the progress of the legislation. This study aims at identifying potential gaps in the current Copernicus product offer for the monitoring of the coastal sector through the elicitation of stakeholder requirements. The methodology is applied to the Italian landscape of users, but it is scalable at European level. The results provide a clear overview of the coastal user requirements, highlighting the common need of integrated information for the management, and represents the basis for defining the coastal services. Full article

(This article belongs to the Special Issue Coastal Sediment Management: From Theory to Practice)

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29 pages, 7286 KiB

Open AccessEditor’s ChoiceArticle

Assessment of the Anthropogenic Sediment Budget of a Littoral Cell System (Northern Tuscany, Italy)

by Sergio Cappucci, Duccio Bertoni, Luigi Enrico Cipriani, Gianfranco Boninsegni and Giovanni Sarti

Water 2020, 12(11), 3240; https://doi.org/10.3390/w12113240 - 19 Nov 2020

Cited by 14 | Viewed by 3147

Abstract

In the present study we describe a straightforward and highly replicable methodology to assess the anthropogenic sediment budget within a coastal system (the Northern Tuscany littoral cell, Italy), specifically selected in a partially natural and partially highly urbanized coastal area, characterized by erosion [...] Read more.

In the present study we describe a straightforward and highly replicable methodology to assess the anthropogenic sediment budget within a coastal system (the Northern Tuscany littoral cell, Italy), specifically selected in a partially natural and partially highly urbanized coastal area, characterized by erosion and accretion processes. The anthropogenic sediment budget has been here calculated as an algebraic sum of sediment inputs, outputs and transfer (m³) within a 40 year time interval (1980–2020). Sediment management strongly influences the sediment budget and, even if its evaluation is crucial to assess the efficiency of a coastal management policy, it is often difficult to quantify the anthropogenic contribution to sedimentary processes. Different types of intervention are carried out by a variety of competent authorities over time (Municipalities, Marinas, Port Authorities), and the correct accountability of sediment budget is no longer known, or possible, for the scientific community. In the Northern Tuscany littoral cell, sedimentation is concentrated in a convergent zone and updrift of port structures, which have determined a series of actions, from offshore dumping and disposal into confined facilities (sediment output), to bypassing and redistribution interventions (sediment transfer); conversely, river mouths and coastal areas protected by groins and barriers are subjected to severe erosion and coastline retreat, resulting in many beach nourishments (sediment input). The majority of coastal protection interventions were carried out to redistribute sand from one site to another within the study area (2,949,800 m³), while the sediment input (1,011,000 m³) almost matched the sediment output (1,254,900 m³) in the considered time interval. A negative anthropogenic sediment budget (−243,900 m³) is here documented. Full article

(This article belongs to the Special Issue Coastal Sediment Management: From Theory to Practice)

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30 pages, 8183 KiB

Open AccessArticle

Assessing Po River Deltaic Vulnerability Using Earth Observation and a Bayesian Belief Network Model

by Andrea Taramelli, Emiliana Valentini, Margherita Righini, Federico Filipponi, Serena Geraldini and Alessandra Nguyen Xuan

Water 2020, 12(10), 2830; https://doi.org/10.3390/w12102830 - 12 Oct 2020

Cited by 9 | Viewed by 2713

Abstract

Deltaic systems are broadly recognized as vulnerable hot spots at the interface between land and sea and are highly exposed to harmful natural and manmade threats. The vulnerability to these threats and the interactions of the biological, physical, and anthropogenic processes in low-lying [...] Read more.

Deltaic systems are broadly recognized as vulnerable hot spots at the interface between land and sea and are highly exposed to harmful natural and manmade threats. The vulnerability to these threats and the interactions of the biological, physical, and anthropogenic processes in low-lying coastal plains, such as river deltas, requires a better understanding in terms of vulnerable systems and to support sustainable management and spatial planning actions in the context of climate change. This study analyses the potential of Bayesian belief network (BBN) models to represent conditional dependencies in vulnerability assessment for future sea level rise (SLR) scenarios considering ecological, morphological and social factors using Earth observation (EO) time series dataset. The BBN model, applied in the Po Delta region in the northern Adriatic coast of Italy, defines relationships between twelve selected variables classified as driver factors (DF), land cover factors (LCF), and land use factors (LUF) chosen as critical for the definition of vulnerability hot spots, future coastal adaptation, and spatial planning actions to be taken. The key results identify the spatial distribution of the vulnerability along the costal delta and highlight where the probability of vulnerable areas is expected to increase in terms of SLR pressure, which occurs especially in the central and southern delta portion. Full article

(This article belongs to the Special Issue Coastal Sediment Management: From Theory to Practice)

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18 pages, 5715 KiB

Open AccessArticle

Sediment Transport near Ship Shoal for Coastal Restoration in the Louisiana Shelf: A Model Estimate of the Year 2017–2018

by Haoran Liu, Kehui Xu, Yanda Ou, Robert Bales, Zhengchen Zang and Z. George Xue

Water 2020, 12(8), 2212; https://doi.org/10.3390/w12082212 - 6 Aug 2020

Cited by 13 | Viewed by 3535

Abstract

Ship Shoal has been a high-priority target sand resource for dredging activities to restore the eroding barrier islands in LA, USA. The Caminada and Raccoon Island pits were dredged on and near Ship Shoal, which resulted in a mixed texture environment with the [...] Read more.

Ship Shoal has been a high-priority target sand resource for dredging activities to restore the eroding barrier islands in LA, USA. The Caminada and Raccoon Island pits were dredged on and near Ship Shoal, which resulted in a mixed texture environment with the redistribution of cohesive mud and noncohesive sand. However, there is very limited knowledge about the source and transport process of suspended muddy sediments near Ship Shoal. The objective of this study is to apply the Regional Ocean Modeling System (ROMS) model to quantify the sediment sources and relative contribution of fluvial sediments with the estuary and shelf sediments delivered to Ship Shoal. The model results showed that suspended mud from the Atchafalaya River can transport and bypass Ship Shoal. Only a minimal amount of suspended mud from the Atchafalaya River can be delivered to Ship Shoal in a one-year time scale. Additionally, suspended mud from the inner shelf could be transported cross Ship Shoal and generate a thin mud layer, which is also considered as the primary sediment source infilling the dredge pits near Ship Shoal. Two hurricanes and one tropical storm during the year 2017–2018 changed the direction of the sediment transport flux near Ship Shoal and contributed to the pit infilling (less than 10% for this specific period). Our model also captured that the bottom sediment concentration in the Raccoon Island pit was relatively higher than the one in Caminada in the same period. Suspended mud sediment from the river, inner shelf, and bay can bypass or transport and deposit in the Caminada pit and Raccoon Island pit, which showed that the Caminada pit and Raccoon Island pits would not be considered as a renewable borrow area for future sand dredging activities for coastal restoration. Full article

(This article belongs to the Special Issue Coastal Sediment Management: From Theory to Practice)

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21 pages, 6841 KiB

Open AccessArticle

Substantial Decrease in Contaminant Concentrations in the Sediments of the Venice (Italy) Canal Network in the Last Two Decades—Implications for Sediment Management

by Roberto Zonta, Daniele Cassin, Roberto Pini and Janusz Dominik

Water 2020, 12(7), 1965; https://doi.org/10.3390/w12071965 - 11 Jul 2020

Cited by 8 | Viewed by 3350

Abstract

The Venice canal network requires periodic intervention to remove sediments that progressively accumulate. The most recent dredging operation was carried out in the second half of the 1990s and early 2000s. These sediments had accumulated over a period of more than 30 years [...] Read more.

The Venice canal network requires periodic intervention to remove sediments that progressively accumulate. The most recent dredging operation was carried out in the second half of the 1990s and early 2000s. These sediments had accumulated over a period of more than 30 years and were highly contaminated with Cd, Cu, Hg, Pb, Zn and PAHs. Sediments deposited after the dredging work were investigated in 2005, 2009, 2014 and 2017 by analysing sediment cores collected from three sites in the canal network. Arsenic, heavy metal and PAH concentrations were observed to be much lower than past values, although Cu, Hg and PAH levels were still relatively high. The high Cu concentrations (mean 161 mg kg⁻¹) are partly due to the widespread use of Cu-based antifouling paint. Current Italian regulations forbid the disposal of dredged sediments with these concentrations inside the lagoon, thereby increasing the cost of canal network maintenance. Full article

(This article belongs to the Special Issue Coastal Sediment Management: From Theory to Practice)

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20 pages, 6440 KiB

Open AccessArticle

An Integrated Approach to Analyze Sedimentary Stock and Coastal Erosion in Vulnerable Areas: Resilience Assessment of San Vicenzo’s Coast (Italy)

by Francesco Bianco, Paolo Conti, Salvador García-Ayllon and Enzo Pranzini

Water 2020, 12(3), 805; https://doi.org/10.3390/w12030805 - 13 Mar 2020

Cited by 8 | Viewed by 3503

Abstract

The assessment of coastal erosion risk is a major challenge, since environmental and geomorphic features, together with sea state parameters, can seriously change the configuration of coastal areas. In addition, the anthropic actions of the coastal communities may also drastically modify the configuration [...] Read more.

The assessment of coastal erosion risk is a major challenge, since environmental and geomorphic features, together with sea state parameters, can seriously change the configuration of coastal areas. In addition, the anthropic actions of the coastal communities may also drastically modify the configuration of the coast in vulnerable areas. In this study, a linkage between regional mapping guidelines and national geological cartography procedures is presented as a meaningful tool in the geomorphic trends analysis for the integrated mapping of the main morphological patterns of San Vincenzo’s coastal area, in the region of Tuscany (Italy). Comparing and joining different procedures—which have different scales and topics—requires adapting the fields and the information provided in maps and databases. In this case study, a GIS morpho-sedimentological approach is developed. This GIS approach enables us to cover several issues simultaneously, such as the representation of coastal active processes, the adaptation of regional and national cartography to coastal erosion assessment, and lastly the calculation of the sedimentary stock analysis, since it represents the first attribute of coasts to be preserved in a resilience-oriented integrated assessment. Full article

(This article belongs to the Special Issue Coastal Sediment Management: From Theory to Practice)

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13 pages, 2101 KiB

Open AccessArticle

Vertical Distribution of Suspended Sediments above Dense Plants in Water Flow

by Yanhong Li, Liquan Xie and Tsung-chow Su

Water 2020, 12(1), 12; https://doi.org/10.3390/w12010012 - 19 Dec 2019

Cited by 7 | Viewed by 3091

Abstract

Plants in natural water flow can improve water quality by adhering and absorbing the fine suspended sediments. Dense plants usually form an additional permeable bottom boundary for the water flow over it. In the flow layer above dense plants, the flow velocity generally [...] Read more.

Plants in natural water flow can improve water quality by adhering and absorbing the fine suspended sediments. Dense plants usually form an additional permeable bottom boundary for the water flow over it. In the flow layer above dense plants, the flow velocity generally presents a zero-plane-displacement and roughness-height double modified semi-logarithmic profile. In addition, the second order shear turbulent moment (or the Reynolds stress) are different from that found in non-vegetated flow. As a result, the turbulent momentum diffusivity of flow and thus the diffusivity of sediment will shift, which will cause the vertical profile of suspended sediment and the corresponding Rouse formula deform. A set of physical experiments with three different diameters of fine suspended sediments was conducted in an indoor water flume. These experiments investigated a new distribution pattern of suspended sediment and the correspondingly deformed Rouse formula in the flow layer over the dense plants. Experimental results showed that above the dense plants, the shear turbulent momentum of flow presented a plant-height modified negative linear profile, which has been proposed by a previous study, and the vertical distribution of fine suspended sediments presented an equilibrium pattern. Based on the plant-modified profiles of flow velocity and the shear turbulent momentum a new zero-plane and plant-height double modified Rouse formula were analytically derived. This double-parameter modified Rouse formula agrees well with the measured profile of suspended sediment concentration experimentally observed in the present study. By adjusting the Prandtl–Schmidt number, i.e., the ratio of sediment diffusivity to flow diffusivity, the double-parameter modified Rouse formula can be applied to submerged dense plant occupied flow. Full article

(This article belongs to the Special Issue Coastal Sediment Management: From Theory to Practice)

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